Buggy code:
public abstract class AbstractTestCase extends LuceneTestCase { protected final String F = "f" ; protected final String F1 = "f1" ; protected final String F2 = "f2" ; protected Directory dir ; protected Analyzer analyzerW ; protected Analyzer analyzerB ; protected Analyzer analyzerK ; protected IndexReader reader ; protected static final String [ ] shortMVValues = new String [ ] { "" , "" , "a<seq2seq4repair_space>b<seq2seq4repair_space>c" , "" , "d<seq2seq4repair_space>e" } ; protected static final String [ ] longMVValues = new String [ ] { "Followings<seq2seq4repair_space>are<seq2seq4repair_space>the<seq2seq4repair_space>examples<seq2seq4repair_space>of<seq2seq4repair_space>customizable<seq2seq4repair_space>parameters<seq2seq4repair_space>and<seq2seq4repair_space>actual<seq2seq4repair_space>examples<seq2seq4repair_space>of<seq2seq4repair_space>customization:" , "The<seq2seq4repair_space>most<seq2seq4repair_space>search<seq2seq4repair_space>engines<seq2seq4repair_space>use<seq2seq4repair_space>only<seq2seq4repair_space>one<seq2seq4repair_space>of<seq2seq4repair_space>these<seq2seq4repair_space>methods.<seq2seq4repair_space>Even<seq2seq4repair_space>the<seq2seq4repair_space>search<seq2seq4repair_space>engines<seq2seq4repair_space>that<seq2seq4repair_space>says<seq2seq4repair_space>they<seq2seq4repair_space>can<seq2seq4repair_space>use<seq2seq4repair_space>the<seq2seq4repair_space>both<seq2seq4repair_space>methods<seq2seq4repair_space>basically" } ; protected static final String [ ] biMVValues = new String [ ] { "\nLucene//Solr<seq2seq4repair_space>does<seq2seq4repair_space>not<seq2seq4repair_space>require<seq2seq4repair_space>such<seq2seq4repair_space>additional<seq2seq4repair_space>hardware." , "\nWhen<seq2seq4repair_space>you<seq2seq4repair_space>talk<seq2seq4repair_space>about<seq2seq4repair_space>processing<seq2seq4repair_space>speed,<seq2seq4repair_space>the" } ; protected static final String [ ] strMVValues = new String [ ] { "abc" , "defg" , "hijkl" } ; @ Override public void setUp ( ) throws Exception { } @ Override public void tearDown ( ) throws Exception { } protected Query tq ( String text ) { } protected Query tq ( float boost , String text ) { } protected Query tq ( String field , String text ) { } protected Query tq ( float boost , String field , String text ) { } protected Query pqF ( String ... texts ) { } protected Query pqF ( float boost , String ... texts ) { } protected Query pqF ( float boost , int slop , String ... texts ) { } protected Query pq ( String field , String ... texts ) { } protected Query pq ( float boost , String field , String ... texts ) { } protected Query pq ( float boost , int slop , String field , String ... texts ) { } protected Query dmq ( Query ... queries ) { } protected Query dmq ( float tieBreakerMultiplier , Query ... queries ) { } protected void assertCollectionQueries ( Collection < Query > actual , Query ... expected ) { } protected List < BytesRef > analyze ( String text , String field , Analyzer analyzer ) throws IOException { List < BytesRef > bytesRefs = new ArrayList < BytesRef > ( ) ; TokenStream tokenStream = analyzer . tokenStream ( field , new StringReader ( text ) ) ; TermToBytesRefAttribute termAttribute = tokenStream . getAttribute ( TermToBytesRefAttribute . class ) ; BytesRef bytesRef = termAttribute . getBytesRef ( ) ; while ( tokenStream . incrementToken ( ) ) { termAttribute . fillBytesRef ( ) ; <START_BUG> bytesRefs . add ( new BytesRef ( bytesRef ) ) ; <END_BUG> } tokenStream . end ( ) ; tokenStream . close ( ) ; return bytesRefs ; } protected PhraseQuery toPhraseQuery ( List < BytesRef > bytesRefs , String field ) { } static final class BigramAnalyzer extends Analyzer { @ Override public TokenStreamComponents createComponents ( String fieldName , Reader reader ) { } } static final class BasicNGramTokenizer extends Tokenizer { public static final int DEFAULT_N_SIZE = 2 ; public static final String DEFAULT_DELIMITERS = "<seq2seq4repair_space>\t\n.," ; private final int n ; private final String delimiters ; private int startTerm ; private int lenTerm ; private int startOffset ; private int nextStartOffset ; private int ch ; private String snippet ; private StringBuilder snippetBuffer ; private static final int BUFFER_SIZE = 4096 ; private char [ ] charBuffer ; private int charBufferIndex ; private int charBufferLen ; public BasicNGramTokenizer ( Reader in ) { } public BasicNGramTokenizer ( Reader in , int n ) { } public BasicNGramTokenizer ( Reader in , String delimiters ) { } public BasicNGramTokenizer ( Reader in , int n , String delimiters ) { } CharTermAttribute termAtt = addAttribute ( CharTermAttribute . class ) ; OffsetAttribute offsetAtt = addAttribute ( OffsetAttribute . class ) ; @ Override public boolean incrementToken ( ) throws IOException { } private int getFinalOffset ( ) { } @ Override public final void end ( ) { } protected boolean getNextPartialSnippet ( ) throws IOException { } protected boolean getNextSnippet ( ) throws IOException { } protected int readCharFromBuffer ( ) throws IOException { } protected boolean isDelimiter ( int c ) { } @ Override public void reset ( Reader input ) throws IOException { } @ Override public void reset ( ) throws IOException { } } protected void make1d1fIndex ( String value ) throws Exception { } protected void make1d1fIndexB ( String value ) throws Exception { } protected void make1dmfIndex ( String ... values ) throws Exception { } protected void make1dmfIndexB ( String ... values ) throws Exception { } protected void make1dmfIndex ( Analyzer analyzer , String ... values ) throws Exception { } protected void make1dmfIndexNA ( String ... values ) throws Exception { } protected void makeIndexShortMV ( ) throws Exception { } protected void makeIndexLongMV ( ) throws Exception { } protected void makeIndexLongMVB ( ) throws Exception { } protected void makeIndexStrMV ( ) throws Exception { } }

Fix:
bytesRefs . add ( BytesRef . deepCopyOf ( bytesRef ) ) ;